Observing the behavior of other people is a fundamental source for the formation of social norms: in fact the behavior of others in the spatial context proximal to the individual might prime and activate voluntary choices. This idea is deeply rooted in various traditions of psychological theory and research, and can be traced back to the early beginning of experimental social psychology. For example, James (1890) proposed the so-called Principle of Ideomotor Action, postulating that simple thinking about a certain action might increase the individual’s tendency to perform it. About one century later, the principle of ideomotor action was assumed as a fundamental mechanism in social cognition research, to explain the priming effects in the automatic activation of social behavior (e.g., Bargh et al. 1996). According to Bargh et al. mental representations and consequent social-behavioral responses might be activated automatically by the mere presence of relevant features in the environment, including the perception of others enacting that behavior. The roots for such an assumption can be found in many domains of psychological research, relating to the concepts of imitation (Koffka 1935; Piaget 1946) and social learning (Bandura 1977), as well as to the process of aggressive behavior following exposure to media communication (e.g., Berkowitz 1984). We argue here that this kind of normative influence has specific spatial roots, which should emerge particularly in the case of those human behaviors having an impact on the quality of our physical environment, and thus having collective implications for the well being of individuals, groups and communities. In fact pro-environmental behaviors have a territorial basis, and are performed in specific places; therefore it is more likely that the ‘‘significant others’’ are represented by those social actors sharing that specific place with the individual (e.g., his/her neighbors). The recycling of household waste is included among these behaviors. The decision on whether separating the household rubbish or not could be influenced more by what our neighbors (compared with our relatives and close friends) do or think about it. Indeed, previous studies showed that descriptive local norms (i.e., individual perceptions of relevant other’s behaviors) are linked to intention to engage in domestic waste recycling (e.g., Carrus et al. 2008). The aim of this paper is to explore the role of social influence stemming from people with whom we share a spatial-physical milieu in everyday life, so as to highlight the role of spatial proximity in the construction of social norms. To this extent, an extended version of the Theory of Planned Behavior (TPB; Ajzen 1991) is used to predict ICSC 2009, 4th International Conference on Spatial Cognition, Rome, 14–18 September 2009.